MediaCaptureFromElement: add support for audio captureStream().

content/renderer/media/html_audio_element_capturer_source_unittest.cc

Index: content/renderer/media/html_audio_element_capturer_source_unittest.cc
diff --git a/content/renderer/media/html_audio_element_capturer_source_unittest.cc b/content/renderer/media/html_audio_element_capturer_source_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e5dd1a75fda918a929602d77f8d26637556dead1
--- /dev/null
+++ b/content/renderer/media/html_audio_element_capturer_source_unittest.cc
@@ -0,0 +1,134 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/memory/weak_ptr.h"
+#include "base/run_loop.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "content/renderer/media/html_audio_element_capturer_source.h"
+#include "media/audio/null_audio_sink.h"
+#include "media/base/audio_parameters.h"
+#include "media/blink/webaudiosourceprovider_impl.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using ::testing::_;
+using ::testing::AllOf;
+using ::testing::InSequence;
+using ::testing::Mock;
+using ::testing::Property;
+
+namespace content {
+
+// These constants represent the sampling rates and samples per buffer for input
+// and output as seen by HTMLAudioElementCapturerSource. For the purpose of the
+// test, both are chunks of 10ms, which happens to be the preferred one of
+// MediaStream Audio Tracks.
+static const int kNumChannelsForTest = 1;
+static const int kBufferDurationMs = 10;
+
+// This value mimics what is provided by WebAudioSourceProviderImpl.
+static const int kPlaybackAudioTrackSamplesPerBuffer = 1024;
+
+static const int kMediaStreamAudioTrackSampleRate = 48000;
+static const int kMediaStreamAudioTrackSamplesPerBuffer =
+    kMediaStreamAudioTrackSampleRate * kBufferDurationMs / 1000;
+
+ACTION_P(RunClosure, closure) {
+  closure.Run();
+}
+
+class MockWebAudioSourceProvider : public media::WebAudioSourceProviderImpl {
+ public:
+  MockWebAudioSourceProvider()
+      : WebAudioSourceProviderImpl(
+            new media::NullAudioSink(base::ThreadTaskRunnerHandle::Get())) {}
+
+  void SetCopyAudioCallback(const CopyAudioCB& callback) override {
+    DVLOG(1) << __FUNCTION__;
+    callback_ = callback;
+
+    // We're super eager and send an AudioBus right after Start().
+    callback_.Run(media::AudioBus::Create(kNumChannelsForTest,
+                                          kPlaybackAudioTrackSamplesPerBuffer),
+                  0 /* delay_milliseconds */, 44100 /* sample_rate */);
+  }
+  void ClearCopyAudioCallback() override {
+    callback_.Reset();
+  }
+
+ protected:
+  ~MockWebAudioSourceProvider() override = default;
+
+ private:
+  CopyAudioCB callback_;
+};
+
+class HTMLAudioElementCapturerSourceTest
+    : public testing::Test,
+      public media::AudioCapturerSource::CaptureCallback {
+ public:
+  HTMLAudioElementCapturerSourceTest()
+      : audio_source_(new MockWebAudioSourceProvider()),
+        html_audio_capturer_(
+            new HtmlAudioElementCapturerSource(audio_source_->AsWeakPtr())) {}
+
+  // media::AudioCapturerSource::CaptureCallback implementation
+  MOCK_METHOD4(Capture,
+               void(const media::AudioBus* audio_source,
+                    int audio_delay_milliseconds,
+                    double volume,
+                    bool key_pressed));
+  MOCK_METHOD1(OnCaptureError, void(const std::string& message));
+
+ protected:
+  // We need some kind of message loop to allow |html_audio_capturer_| to
+  // schedule capture events.
+  const base::MessageLoopForUI message_loop_;
+
+  scoped_refptr<MockWebAudioSourceProvider> audio_source_;
+  scoped_refptr<HtmlAudioElementCapturerSource> html_audio_capturer_;
+};
+
+// Constructs and destructs all objects, in particular |html_audio_capturer_|
+// and its inner object(s). This is a non trivial sequence.
+TEST_F(HTMLAudioElementCapturerSourceTest, ConstructAndDestruct) {}
+
+TEST_F(HTMLAudioElementCapturerSourceTest, InitializeStartAndStop) {
+  InSequence s;
+
+  base::RunLoop run_loop;
+  base::Closure quit_closure = run_loop.QuitClosure();
+
+  // Similar to what WebRtcAudioCapturer::SetCapturerSourceInternal() does.
+  const media::AudioParameters params(
+      media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
+      media::GuessChannelLayout(kNumChannelsForTest),
+      kMediaStreamAudioTrackSampleRate /* sample_rate */,
+      16 /* bits_per_sample */,
+      kMediaStreamAudioTrackSamplesPerBuffer /* frames_per_buffer */);
+  html_audio_capturer_->Initialize(params, this, 0 /* session_id */);
+
+  EXPECT_CALL(
+      *this,
+      Capture(AllOf(Property(&media::AudioBus::channels, kNumChannelsForTest),
+                    Property(&media::AudioBus::frames,
+                             kMediaStreamAudioTrackSamplesPerBuffer)),
+              _, 1.0, false))
+      .Times(1);
+  EXPECT_CALL(
+      *this,
+      Capture(AllOf(Property(&media::AudioBus::channels, kNumChannelsForTest),
+                    Property(&media::AudioBus::frames,
+                             kMediaStreamAudioTrackSamplesPerBuffer)),
+              _, 1.0, false))
+      .Times(1)
+      .WillOnce(RunClosure(quit_closure));
+  html_audio_capturer_->Start();
+  run_loop.Run();
+
+  html_audio_capturer_->Stop();
+  Mock::VerifyAndClearExpectations(this);
+}
+
+}  // namespace content